Erm.... potential cooked auto box...

[215cu]

The chariot is due it's MOT next month with a new garage (on account of moving home), it's come highly recommended from Slade's Garage in Penn. If you have ever seen what they sell in Slade's then you'll know that's quite a recommendation.

So doing the MOT prep with all the service items bar the oil change (as I can't be arsed with the oil disposal crap) I checked the ATF.

It's gone a purple colour (definitely not the cherry red of Type F I'm used to) but it doesn't smell burnt. The fluid was changed four years ago by the previous owner (as much as you can) and it's always been a reasonable colour.

I topped it up (as the cork seals do weep) as a matter of course, however, there was one spell where despite the dipstick reading, the gearbox started doing strange things and it could well have been running low. I topped it (requiring a good pint and a half) and it was fine.

More recently, I've noticed it either holds 1st for too long or drops 1st straight to second. 2nd to 3rd upchange can be as expected or occasionally it will require me to lift off the throttle to engage 3rd, sometimes manual intervention is required shifting to D2 and then changing to D3 to make it happen.

Sometimes the change is hardly noticeable, sometimes it will shunt. Once the gear is engaged though, it locks up nicely allowed for good progress.

And for the majority of the time, it's a well behaved smooth box.

It's always been a bit of a 'queerbox' since I've had it and it's taken some punishment, the rear diff was loose causing prop vibration and also I had a hard to diagnose engine mount problem which would have had the prop slightly misaligned from the box to the rear diff.

The gearbox is a Borg Warner 35. They are normally basic, no-fuss, no-nonsense boxes that have a good reputation (despite their age) of being bombproof.

Add to the mix that there is a whine at idle that's getting louder and also definitely noticable when making progress.

Hence my concerns, this gearbox will be a soon to be deceased gearbox.

Now money is an object (my wife is a very proactive bank manager )and I think the only real danger is a pump going leaving me with no gears and no traction.

My preferred option is a straight replacement for a recon box or alternative I've heard is the BW65 is a more pleasant proposition.

All advice greatly appreciated either on the suspected longevity of my current 'gearbox' or on the whole recon/replace ideas.

Cheers in advance.

Edited by 215cu on Monday 3rd March 12:03

[scovette]

If you do end up replacing the box it might be an idea to fit a 4-speed o/d auto instead of the BW65 for better cruising mpg?

[215cu]

Yeah, it's a case of changing the bellhousing for anything else other than a BW35/65. One very popular conversion is a ZF 4-speed but it's down to the availability of the ZF box. LDV did a Rover V8 Ambulance and this came with a very nice ZF... however these are quite rare but do occasionally turn up.

After that, you are into the domain of recalibrating things like speedo and odo, etc, etc and also it makes mechanics desert you when you mention something like 'non-standard' gearbox.

Should also add, during the last MOT they ran a diagnostic chemical test on a sample of the fluid - came back fine. Might ask for one at MOT time.

[Firefox1]

You haven't said what age the box is or the milage but it could be that it just needs an oil and filter change which usually is quite straight forward, if you have a decent workshop manual it should help.

[tyre_tread]

Mike, there is a guy called Harvey (although that's his handle & not his real name) on the Rover P5 Club forum that put me in touch with the guy hat built a replacement BW35 for me.

"Harvey" is very knowledgeable on all things Rover as he is an ex time served Rover mechanoc of the old school. I'll PM you his details.

ETA: your profile doesn't allow PM's so email me at [e-mail] if you want his contact details.

Edited by tyre_tread on Monday 3rd March 22:20

[215cu]

tyre_tread said:

Mike, there is a guy called Harvey (although that's his handle & not his real name) on the Rover P5 Club forum that put me in touch with the guy hat built a replacement BW35 for me.

"Harvey" is very knowledgeable on all things Rover as he is an ex time served Rover mechanoc of the old school. I'll PM you his details.

ETA: your profile doesn't allow PM's so email me at [e-mail] if you want his contact details.

Edited by tyre_tread on Monday 3rd March 22:20

Thanks Alan, it's a small world as he's active on the P6 Rover Owners Club forum too and he's given me a reply there (I am so glad they've got that board up and running again) and I've supplied some more info.

The 'cooked' fluid could simply be the additive altering the colour as it doesn't smell burnt which is more important.

The fact that the issues are all up/downchange related and not the 'legs' of the box as it locks up nicely and doesn't need the engine to wind out to make good progress suggests the bands are ok which is a relief and the niggles are throttle related.

So it's looking like a round of early checks regarding throttle linkage bushes (which do wear and cause all sorts of selector issues) and kickdown cable setting/play. It could be a simple thing like the kickdown cable sticking or needs adjustment which might explain the whine at idle.

I've got the workshop manual so it's a case going through the motions with the manual to check the kickdown cable.

There's no harm in getting hold of 10 litres of TQF and asking the MOT garage to empty, fill, empty, fill it to get at the fluid in the convertor and refresh it as much as possible. A filter change would be sensible too.

If this is no remedy then it's a case of finding a local auto specialist to cast their eyes over it. I'm loathed to spent out on another box just as my respray / interior refresh fund is developing nicely.

As to the age of the box, well, it's 39 years old with 89K miles on the clock. Whilst not the most sophisticated auto box they were used by countless cars, Ford, Volvo, Triumph, Rolls, Aston, Rover mainly because they were hardy boxes well suited to a range of engines.

Edited by 215cu on Tuesday 4th March 09:59

Edited by 215cu on Tuesday 4th March 10:18

[jith]

215cu said:

tyre_tread said:

Mike, there is a guy called Harvey (although that's his handle & not his real name) on the Rover P5 Club forum that put me in touch with the guy hat built a replacement BW35 for me.

"Harvey" is very knowledgeable on all things Rover as he is an ex time served Rover mechanoc of the old school. I'll PM you his details.

ETA: your profile doesn't allow PM's so email me at [e-mail] if you want his contact details.

Edited by tyre_tread on Monday 3rd March 22:20

Thanks Alan, it's a small world as he's active on the P6 Rover Owners Club forum too and he's given me a reply there (I am so glad they've got that board up and running again) and I've supplied some more info.

The 'cooked' fluid could simply be the additive altering the colour as it doesn't smell burnt which is more important.

The fact that the issues are all up/downchange related and not the 'legs' of the box as it locks up nicely and doesn't need the engine to wind out to make good progress suggests the bands are ok which is a relief and the niggles are throttle related.

So it's looking like a round of early checks regarding throttle linkage bushes (which do wear and cause all sorts of selector issues) and kickdown cable setting/play. It could be a simple thing like the kickdown cable sticking or needs adjustment which might explain the whine at idle.

I've got the workshop manual so it's a case going through the motions with the manual to check the kickdown cable.

There's no harm in getting hold of 10 litres of TQF and asking the MOT garage to empty, fill, empty, fill it to get at the fluid in the convertor and refresh it as much as possible. A filter change would be sensible too.

If this is no remedy then it's a case of finding a local auto specialist to cast their eyes over it. I'm loathed to spent out on another box just as my respray / interior refresh fund is developing nicely.

As to the age of the box, well, it's 39 years old with 89K miles on the clock. Whilst not the most sophisticated auto box they were used by countless cars, Ford, Volvo, Triumph, Rolls, Aston, Rover mainly because they were hardy boxes well suited to a range of engines.

Edited by 215cu on Tuesday 4th March 09:59

Edited by 215cu on Tuesday 4th March 10:18

215, I seem to remember that the issue of the Type 35 was discussed on here before, and I think perhaps yourself and someone else had made the remrk about it being bombproof and a hardy 'box.
As one who actually worked on these things at the time let me assure you that this was definitely not the case.
The Type 35 was developed as a very compact and lightweight 'box for small, low torque applications, and when used in this manner it was perfectly acceptable. E.G. the Rover 2000SC auto very seldom gave trouble, as was the case with four cylinder Fords and Triumphs, etc.
The problems began when Rover and others used it in larger capacity, high torque applications.
The largest number of warranty claims that we carried out on this 'box came from usage on the P5 V8 and the Daimler 250 saloon, both very heavy, high torque vehicles.
Failure always resulted in severe internal damage to the convertor, the convertor drive plate, particularly on the Triumph 2000, and the clutch plates.
Your 'box sounds as if either the internal splines in the clutch discs are beginning to chew and therefore stick causing exactly the symptoms you describe, or the convertor turbine bearing is worn, causing the whine you describe at idle.
On the plus side the same whine can also be caused by cavitation in the hydraulic system, i.e. air frothing the fluid due to a partially choked micronic sump filter.
I would drop the sump, clean it out and renew the filter.
If you find a lot of what looks like silver paste, or worse still actual metal fragments in the sump around the magnet, you have a problem.
If not, it might just do the trick.
If you are going to change the 'box, I would opt for anything more modern that you can get in.
Modern autos are light years ahead of the older ones, and far more reliable.
If you fit a four speed, you should notice a vast inprovement in fuel consumption.

[215cu]

jith said:

215cu said:

tyre_tread said:

Mike, there is a guy called Harvey (although that's his handle & not his real name) on the Rover P5 Club forum that put me in touch with the guy hat built a replacement BW35 for me.

"Harvey" is very knowledgeable on all things Rover as he is an ex time served Rover mechanoc of the old school. I'll PM you his details.

ETA: your profile doesn't allow PM's so email me at [e-mail] if you want his contact details.

Edited by tyre_tread on Monday 3rd March 22:20

Thanks Alan, it's a small world as he's active on the P6 Rover Owners Club forum too and he's given me a reply there (I am so glad they've got that board up and running again) and I've supplied some more info.

The 'cooked' fluid could simply be the additive altering the colour as it doesn't smell burnt which is more important.

The fact that the issues are all up/downchange related and not the 'legs' of the box as it locks up nicely and doesn't need the engine to wind out to make good progress suggests the bands are ok which is a relief and the niggles are throttle related.

So it's looking like a round of early checks regarding throttle linkage bushes (which do wear and cause all sorts of selector issues) and kickdown cable setting/play. It could be a simple thing like the kickdown cable sticking or needs adjustment which might explain the whine at idle.

I've got the workshop manual so it's a case going through the motions with the manual to check the kickdown cable.

There's no harm in getting hold of 10 litres of TQF and asking the MOT garage to empty, fill, empty, fill it to get at the fluid in the convertor and refresh it as much as possible. A filter change would be sensible too.

If this is no remedy then it's a case of finding a local auto specialist to cast their eyes over it. I'm loathed to spent out on another box just as my respray / interior refresh fund is developing nicely.

As to the age of the box, well, it's 39 years old with 89K miles on the clock. Whilst not the most sophisticated auto box they were used by countless cars, Ford, Volvo, Triumph, Rolls, Aston, Rover mainly because they were hardy boxes well suited to a range of engines.

Edited by 215cu on Tuesday 4th March 09:59

Edited by 215cu on Tuesday 4th March 10:18

215, I seem to remember that the issue of the Type 35 was discussed on here before, and I think perhaps yourself and someone else had made the remrk about it being bombproof and a hardy 'box.
As one who actually worked on these things at the time let me assure you that this was definitely not the case.
The Type 35 was developed as a very compact and lightweight 'box for small, low torque applications, and when used in this manner it was perfectly acceptable. E.G. the Rover 2000SC auto very seldom gave trouble, as was the case with four cylinder Fords and Triumphs, etc.
The problems began when Rover and others used it in larger capacity, high torque applications.
The largest number of warranty claims that we carried out on this 'box came from usage on the P5 V8 and the Daimler 250 saloon, both very heavy, high torque vehicles.
Failure always resulted in severe internal damage to the convertor, the convertor drive plate, particularly on the Triumph 2000, and the clutch plates.
Your 'box sounds as if either the internal splines in the clutch discs are beginning to chew and therefore stick causing exactly the symptoms you describe, or the convertor turbine bearing is worn, causing the whine you describe at idle.
On the plus side the same whine can also be caused by cavitation in the hydraulic system, i.e. air frothing the fluid due to a partially choked micronic sump filter.
I would drop the sump, clean it out and renew the filter.
If you find a lot of what looks like silver paste, or worse still actual metal fragments in the sump around the magnet, you have a problem.
If not, it might just do the trick.
If you are going to change the 'box, I would opt for anything more modern that you can get in.
Modern autos are light years ahead of the older ones, and far more reliable.
If you fit a four speed, you should notice a vast inprovement in fuel consumption.

Really? So why then was the BW35 fitted to the Charger and also a series of Fairlane cars if it's only meant for small, low torque applications? Also, your personal opinion isn't borne out by the many qualified opinions of many mechanics servicing and looking after a raft of marques all using the same gearbox for a series of applications?

Also, if you bothered to read the experience of using the box, it has no problems locking up (suggesting band and clutch plate problems), locking up nicely doing so without the tell-tale signs of prolonged engine wind-out and slipping during an application of revs.

We'd got to the point (after speaking to a very qualified automatic gearbox specialist) that the kickdown cable is probably sticking and possibly a filter change.

Incidentally, the chemical test I had done on the box last year showed no nasties. Also, ATF colouration change is more likely due to Forte additives than anything else.

I don't know why you have it in for me (see BMW 2000) but we are all entitled to our opinion. Thank you for the technical explanation and in getting to the point that we'd already reached without your contribution and the accompanying sanctimonious attitude.

Free advice is exactly that, disposable.

So guess what I'll be doing with yours.

Edited by 215cu on Friday 7th March 19:59

[tyre_tread]

I'm also told that the BW35 was used in the tugs at airports that are used to pull aircraft on and off ther stands so if that isn't a high torque usage then I don't know what is.

[215cu]

tyre_tread said:

I'm also told that the BW35 was used in the tugs at airports that are used to pull aircraft on and off ther stands so if that isn't a high torque usage then I don't know what is.

Says it all really.

The workshop manual has a very good diagnostic matrix which for the issues I was having listed fluid level, kickdown and engine idle as the three main actions before going into the autobox mechanicals. Using up/downchange charts for light, full and kickdown throttle I could work out what was supposed to be going on. I went out to get the current settings and then made adjustments and another run.

It seems there is a couple of throttle sensitive mph ranges I wasn't aware of as there are two kickdown ranges one at 30mph and another 40-50mph. So that might explain some the 'characteristics' I was experiencing.

After a couple of run-outs it seems the kickdown cable was slightly out as the light throttle upchange ranges were a little on the high side especially 2 to 3. So winding it back on the adjuster to shorten the cable a little it's now acceptable. I also adjusted the slow running screws on the carbs to lower the engine idle and it's a much smoother proposition crawling through town.

Fortunately as it was quiet on the roads so I even got to use the 50mph full throttle kickdown and holding the throttle it changed up to 3rd bang on the middle of the range at 70. All the reverse tests were fine at low speed as well.

The whine seems to have subsided a lot and I suspect because the box is now topped up but the pesky cork seal weeps fluid when it's warm. I think a few of the maladies can be traced back to losing fluid over the course of a couple of months, low to high levels are almost 1 1/2 pints.

The manual suggests a fluid change every 5000 miles and it's nearly up to that so I've managed to source a filter and new seal. I'll flush the box as much as I can and fit the new filter. I usually use a Forte conditioner but I'll hold fire on that and see if the fluid degrades.

Needless to say I'm relieved, sourcing the filter through Wadhams, they quoted £700+vat to re-con my box. Ouch.

I'll keep more of an eye on it and hope that a new seal can cure the incontinence

Edited by 215cu on Saturday 8th March 12:47